Just wondering can anyone tell me if the AI is smart on this game ie being able to adapt to different situations. For example if I place an army away from my base guarding a resource position will the AI attack them or still go for my main base. And does the AI build tunnels?

anyone come on guys. This forum cant be completely dead lol this is the best RTS ever

Earth 2140's AI here on GOG is severely crippled as you can read from a thread about it.
Other games have quite good AI (by mu standards, which doesn't mean anything for you).

I have bought the game now and I have to say it is very good. I actually do think the AI is pretty good. Only problem is it can be very repetive on easy ie always attacking in the same place, but overall I think the AI is good. Its also a very addictive game I spent 2 hours on one game yesterday. They just dont make strategy games as good as earth anymore which is a shame. And about the AI on 2140. I used to have that game and the AI was good on it. Can you not play the Dosbox version on cog?

I still have my original CD of Earth 2140. When I was playing it back then, the AI was really challenging, you had to have some AA defense (=rockets) in base, so enemy transporters couldn't unload infantry in your base and capture your buildings. In GOG's version enemy units only return fire and some off-map units attack if you trigger some script (not that many).
I've even sent them image of my CD on their FTP and they confirmed that the AI in their version is neutered. Sadly, it all depends to which version they get rights.

Its a shame that the AI is poor on the GOG version. Might have to get 2140 off amazon. Btw have you played earth 2160?

Yes, I have, but not that much.

Whats it like. I have heard mixed reviews about it.

Call it Earth 2150 with infantry, which is fine for me, and add hireable heroes.
Though I don't like that the ED has (yet again) changed its philosophy.
In 2140 they were some Asian uber country, in 2150 communist-like army and in 2160 something akin to US army.